The objective of this study is to evaluate chemical hazards and risks associated with the accidental release of Li-ion battery electrolyte into an enclosed space. Because of the high volatility and reactivity of some components of contemporary Li-ion battery electrolytes this study focuses on the inhalation toxicity of released and generated gas phase components. These include evaporated solvents and HF as a decomposition product of the widely used LiPF6 salt. Our calculations show that at room temperature a small electrolyte release can result in the formation of a toxic atmosphere with concentration of the released compound reaching an acute exposure limit where irreversible and other serious health effects are expected to occur. For most contemporary electrolyte components this corresponds to a release of less than ca. 250 ml in a volume occupied by a medium-size car with a clearance of 1 m, i.e. ca. 62 m3. Further research, required as part of the thorough risk analysis, is identified.